This invention relates to an apparatus for two-sided printing. More particularly, this invention relates to an assembly responsive to computer generated signals for printing a document on two sides.
At the present time, thousands of banks, brokerage houses and other financial institutions are printing millions of weekly, bi-weekly and monthly statements on one side of pre-printed statement forms. For the most part, these statements are printed off of mainframe or large-scale mini-computers. Affordable printers capable of handling mainframe and minicomputer output are either chain or dot-matrix printers. Consequently, printing both sides of paper having the conventional quality would masticate the paper.
Conventional two-sided photocopying and book printing present problems which have perhaps inhibited efforts to develop two-sided printing of financial type statements. Such problems include a warping of the paper which results from the high levels of heat employed. More moisture flees from the side of the paper in contact with the heated elements than from the more remote side of the paper. In addition, the deposition of electrostatic charges causes the paper sheets to cling to one another and to other surfaces. Both the warping of the paper sheets and the deposited electrostatic charge cause paper jams in the machinery. Avoiding or clearing the paper jams requires personnel to be present to monitor and correct problems as they occur. Sometimes, papers printed on one side are placed aside for flattening prior to printing on the opposite side. Such efforts increase costs and delay the production of the desired documents.
An object of the present invention is provide a printing system or assembly for printing two-sided documents in response to computer-generated signals encoding the documents.
Another object of the present invention is to provide such a system or assembly which can handle mainframe and other large-scale computer output.
A further object of the present invention is to provide such a system or assembly which prints on each side of a sheet of paper in real time.
Yet another object of the present invention is to provide such a system or assembly which can utilize laser printer technology and basic or conventional printer driver programming.
An additional object of the present invention is to provide such a system or assembly which is simple to manufacture, assemble and implement.
These and other objects of the present invention will be apparent from the descriptions and drawings hereof
A printing assembly comprises, in accordance with a general embodiment of the present invention, a first printer for printing documents encoded in computer generated signals and a second printer for printing documents encoded in computer generated signals. The documents generally include alphanumeric characters, charts and graphics. A computer for generating a signal encoding a multiple page document is coupled via connection componentry to the printers for transmitting odd pages in encoded form to one of the printers and even pages to the other printer.
The paper used by the printing assembly may be a series of paper sheet portions connected to one another in a continuous web of paper. In that event, the printers are connected in tandem to one another via the multiple-page continuous paper web. The web extends from a paper output port of the first printer to a paper feed port of the second printer.
Preferably, the printers are disposed one above the other, the web of paper being simply inverted in a U or C shape between the output port of the first printer and the paper feed port of the second printer. A tensioning device may be placed in contact with the web between the paper output port of the first printer and the paper feed port of the second printer for guiding the web and providing it with a predetermined amount of tension. The tensioning device exemplarily includes a spring loaded, electrically conductive element such as a roller which is electrically grounded to siphon away electrostatic charge deposited on the paper by the first printer.
Preferably, the connection componentry includes a page splitting module for detecting odd pages and even pages in the document and separating odd pages from even pages. The connection componentry further includes a synchronizer for timing the operation of the first printer and the second printer so that opposite sides of essentially every sheet portion bear consecutive pages. The connection componentry may additionally include an electronic buffer.
In a more specific embodiment of the present invention, the printers are off-the-shelf components, preferably desk-top type laser printers.
A device for enabling two-sided printing comprises, pursuant to another embodiment of the present invention, a page-splitting component for detecting odd pages and even pages in a document encoded in a computer-generated signal and for separating odd pages and even pages in the document. A first coupling element connects an input of the page-splitting component to a computer, while a second coupling element connects an output of the page-splitting component to a first printer and a third coupling element connects another output of the page-splitting component to a second printer.
In accordance with another feature of the present invention, a timing module is operatively connected to the page spitting component and at least one of the coupling elements for timing the operation of the printers so that opposite sides of a plurality of paper sheet portions fed from the paper output port of one printer to the paper feed port of the other printer bear consecutive pages. The timing module includes a delay for transmitting pages of a given document over the one coupling element only after lapse of a predetermined interval after an initial transmission of pages of the document over the other coupling element.
In a printing method in accordance with the present invention, a first printer for printing documents encoded in computer generated digital signals is disposed in tandem to a second printer for printing documents encoded in computer generated digital signals. A computer for generating a digital signal encoding a multiple page document is operatively connected to data inputs of the two printers. Odd pages of the multiple page document are then transmitted in encoded form from the computer to one of the printers and even pages of the multiple page document are transmitted from the computer to the other printer. The printers then print the respective even and odd pages on opposing sides of paper sheets which are guided from a paper output port of a first printer to a paper feed port of the other printer.
Generally, the paper sheets are provided in a Z-fold type continuous web. The web extends from the paper output port of the first printer to the paper feed port of the second printer.
Pursuant to a feature of the present invention, the connecting of the computer to the printers includes connecting an output terminal of the computer to an input terminal of a buffer interface and also connecting the buffer interface to the data inputs of the printers. The buffer interface is then operated to detect odd pages and even pages in the document and to separate odd pages from even pages. In addition, the buffer interface is operated to time or synchronize the operation of the printers so that opposite sides of essentially every sheet portion of the paper web bear consecutive pages.
In accordance with another feature of the present invention, the printers are disposed one above the other. Where a continuous web of paper is used, the web is simply inverted in a U or C shape between the output port of the first printer and the paper feed port of the second printer. A guide such as a tensioning roller is placed in contact with the web between the output port of the first printer and the feed port of the second printer. Where the paper sheets are separate, a guide such as an arcuate or curved surface is provided to direct the paper sheets from the first printer to the second printer.
A printing system or assembly in accordance with the present invention is a high-volume printing system which can print customer data, e.g., on financial statements, in real time, using black and white laser printing technology and basic or conventional printer driver programming.
A printing system or assembly in accordance with the present invention reduces the number of sheets of paper necessary to print financial statements by 50% or more, concomitantly reducing printing and mailing costs. In addition, the system eliminates the need to use expensive pre-printed paper stock for financial statements. Logos may be printed on the front of each sheet in real time, while legal compliance information is printed only on the last face of a statement. The quality of the printed characters may be significantly improved over conventional methods of statement printing, up to the highest laser standards. Moreover, development costs can be substantially decreased through the utilization of existing (off-the-shelf) laser printer engines (preferably using powerful RISC processors).
A printing system or assembly for printing two-sided documents in accordance with the present invention can handle mainframe and other large-scale computer output. The printing occurs without essential delay (in real time) in response to computer generated signals. In contrast, in photocopying and other printing methods, there is a substantial delay between printing of one side and printing of the opposing side.
A system or assembly in accordance with the present invention can utilize laser printer technology and basic or conventional printer driver programming.